Position pointer

Abstract

A position pointer is provided for indicating a position on a sensor of a position detection device. The position pointer includes an elongate pointer body having a distal end and a proximal end; a first electrode disposed near the distal end; and a second electrode different from the first electrode and disposed near the distal end, wherein both the first and second electrodes are capacitively coupleable with the sensor of the position detection device. The position pointer includes a detection circuit configured to intermittently detect signals transmitted from the position detection device; a signal circuit configured to generate a position signal to be transmitted to the position detection device; and a transmission circuit configured to control transmission of the position signal. The transmission circuit, based on a detection result of the detection circuit, controls transmission of the position signal via the first electrode.

The invention claimed is: 
     
         1 . A position pointer for indicating a position on a sensor of a position detection device, the position pointer comprising:
 a pointer body having a distal end;   a central electrode disposed near the distal end of the pointer body;   a detection circuit configured to output a control signal indicative of a result of detecting a first signal transmitted from the position detection device;   a power storage circuit configured to store driving power supplied from an external device; and   a power supply control circuit configured to control the power storage circuit, in response to the control signal exhibiting a first control to indicate detection of the first signal by the detection circuit, to supply the stored driving power to a predetermined circuit.   
     
     
         2 . The position pointer of  claim 1 , comprising:
 a Light Emitting Diode configured to emit light based on the detection of the first signal by the detection circuit.   
     
     
         3 . The position pointer of  claim 1 , comprising:
 a peripheral electrode surrounding the central electrode;   wherein the detection circuit is configured to detect the first signal transmitted from the position detection device via the central electrode or the peripheral electrode.   
     
     
         4 . The position pointer of  claim 3 , wherein the central electrode and the peripheral electrode are capacitively coupleable with the sensor of the position detection device. 
     
     
         5 . The position pointer of  claim 1 , wherein the power supply control circuit is configured to generate a stabilized driving voltage for driving the position pointer from an output of the driving power stored in the power storage circuit. 
     
     
         6 . The position pointer of  claim 5 , wherein the power supply control circuit is configured to generate the stabilized driving voltage by performing Pulse Width Modulation (PWM) of the driving power. 
     
     
         7 . The position pointer of  claim 5 , wherein the power supply control circuit, based on the detection circuit not detecting the first signal, intermittently supplies the stabilized driving voltage to the detection circuit, to cause the detection circuit to correspondingly intermittently attempt to detect the first signal. 
     
     
         8 . The position pointer of  claim 5 , comprising:
 a stabilizing capacitor configured to store the stabilized driving voltage.   
     
     
         9 . The position pointer of  claim 8 , comprising:
 a transistor coupled to the stabilizing capacitor;   wherein the power supply control circuit is coupled to a gate of the transistor.   
     
     
         10 . The position pointer of  claim 9 , wherein the power supply control circuit generates the stabilized driving voltage by controlling the transistor to perform Pulse Width Modulation (PWM) of the driving power supplied from the power storage circuit. 
     
     
         11 . The position pointer of  claim 1 , wherein the power storage circuit is configured to store the driving power which is wirelessly supplied from the external device. 
     
     
         12 . The position pointer of  claim 1 , comprising:
 a coupling node to be coupled to the external device;   wherein the power storage circuit is configured to receive the driving power supplied from the external device via the coupling node.   
     
     
         13 . The position pointer of  claim 1 , wherein the external device is the position detection device. 
     
     
         14 . The position pointer of  claim 1 , wherein the power storage circuit is configured to receive the driving power electromagnetically from the external device. 
     
     
         15 . The position pointer of  claim 1 , wherein the power storage circuit is configured to receive the driving power using a coil which is coupled to the power storage circuit. 
     
     
         16 . A position pointer for indicating a position on a sensor of a position detection device, the position pointer comprising:
 a pointer body having a distal end;   a central electrode disposed near the distal end of the pointer body;   a detection circuit configured to output a control signal indicative of a result of detecting a first signal transmitted from the position detection device;   a coupling circuit formed of a coil and configured to receive driving power wirelessly supplied from an external device via the coil;   a power storage circuit coupled to the coupling circuit and configured to store the driving power; and   a power supply control circuit configured to control the power storage circuit, in response to the control signal exhibiting a first control to indicate detection of the first signal by the detection circuit, to supply the stored driving power to a predetermined circuit.   
     
     
         17 . The position pointer of  claim 16 , comprising:
 a Light Emitting Diode configured to emit light based on the detection of the first signal by the detection circuit.   
     
     
         18 . The position pointer of  claim 16 , comprising:
 a peripheral electrode surrounding the central electrode;   wherein the detection circuit is configured to detect the first signal transmitted from the position detection device via the central electrode or the peripheral electrode.   
     
     
         19 . The position pointer of  claim 18 , wherein the central electrode and the peripheral electrode are capacitively coupleable with the sensor of the position detection device. 
     
     
         20 . The position pointer of  claim 16 , wherein the power supply control circuit is configured to generate a stabilized driving voltage for driving the position pointer from an output of the driving power stored in the power storage circuit. 
     
     
         21 . The position pointer of  claim 20 , wherein the power supply control circuit, based on the detection circuit not detecting the first signal, intermittently supplies the stabilized driving voltage to the detection circuit, to cause the detection circuit to correspondingly intermittently attempt to detect the first signal. 
     
     
         22 . The position pointer of  claim 20 , comprising:
 a stabilizing capacitor configured to store the stabilized driving voltage.   
     
     
         23 . The position pointer of  claim 22 , comprising:
 a transistor coupled to the stabilizing capacitor;   wherein the power supply control circuit is coupled to a gate of the transistor.   
     
     
         24 . The position pointer of  claim 23 , wherein the power supply control circuit generates the stabilized driving voltage by controlling the transistor to perform Pulse Width Modulation (PWM) of the driving power supplied from the power storage circuit.